The invention concerns a pivot device comprising a first hinge part, a second hinge part that is pivotable relative to the first hinge part about a pivot axis, and a blocking device that secures the hinge parts with regard to forward and backward pivoting.
WO 2005/031097 A1 discloses a pivot device with two hinge parts and a correlated blocking device. It serves for pivotably connecting vehicle doors to the body of a motor vehicle. The first hinge part as a door hinge part is secured on the vehicle door and the second hinge part as a body hinge part is secured on the motor vehicle body so that upon opening of the vehicle door the two hinge parts pivot relative to one another. The hinge is provided with a blocking device. It includes a blocking path with several blocking contours that at certain pivot angles of the door hinge part causes blocking by means of a correlated blocking member. Unwanted pivot movements of the hinge parts or unwanted opening or closing of the vehicle door are inhibited in this way. Only upon application of a preset pivoting force is it possible to release the door from the blocking action.
A further pivot device provided with a blocking device is disclosed in DE 198 33 924 A1. In this connection, the two hinge parts are connected by a relatively long screw bolt. It is seated with its head fixedly in the first hinge part and engages with its thread a corresponding thread of the second hinge part. Pivoting of the hinge parts relative to one another causes axial expansion of the screw bolt. This has the result that friction surfaces on the first and second hinge parts, between which a disk-shaped bearing plate is arranged, rub against one another with increasing normal force so that a blocking action will result that increases with the pivot angle. In operation, the friction surfaces that are positioned transversely to the hinge axis and the bearing plate are exposed to a significant surface pressure that causes great wear. This can lead over time to discontinuities in the initially uniformly increasing blocking action over the course of extended use.
A pivot device with a blocking action that operates in the circumferential direction is disclosed in DE 197 26 536 A1. In this device, the two hinge parts are provided with bushings inserted into one another and rotatable relative to one another. The inner surface of the outer bushing and the outer surface of the inner bushing that is formed by the hinge bolt are provided with slightly cam-shaped friction contours that are oversized relative to one another across part of the circumference. The outer bushing is therefore designed to be deformable. In spite of this, as a function of the pivot angle, individual surface areas of the friction contours are pressure-loaded much more than other surface areas. The non-uniform surface pressure causes increased local wear. This, over time, can lead to an increasingly undefined blocking action.
It is therefore the object of the invention to provide a pivot device comprising a blocking device which pivot device, even after an extended period of operation, still operates with a defined blocking action.